The invention relates to an arrangement for monitoring a Yankee cylinder comprising a heated outer surface for directing a treatment effect to the moving tissue web to be manufactured.
The invention relates also to a method for monitoring a Yankee cylinder comprising a heated outer surface for directing a treatment effect to the moving tissue web to be manufactured.
A tissue machine comprises a Yankee cylinder that is used for drying a tissue web to be manufactured. The Yankee cylinder comprises a heated outer surface against which the tissue web to be manufactured is brought for drying the tissue web. The tissue web is an example of a fibrous web containing lignocellulose and the tissue machine is an example of a fibrous web manufacturing machine for manufacture a fibrous web. The Yankee cylinder, in turn, provides an example of a fibrous web processing apparatus that is a part of a fibrous web manufacturing machine and comprises a heated treatment surface for directing a treatment effect, i.e. a drying effect, to the moving fibrous web to be manufactured.
For monitoring a condition or a performance of the Yankee cylinder, such as wear of the outer surface of the Yankee cylinder or a drying performance thereof, a surface topography or a drying performance of the Yankee cylinder is monitored. In prior art, the surface topography of the Yankee cylinder has been determined for example with a measurement instrument that is configured to follow the outer surface of the Yankee cylinder and any roughness therein. The measurement instrument like that may for example comprise a micrometer and a buzzer running along a wire tensioned across the outer surface of the Yankee cylinder. The drying performance of the Yankee cylinder has been evaluated for example by using high speed infrared cameras arranged to take infrared pictures of the outer surface of the Yankee cylinder or by using other additional or auxiliary devices intended for the specific purpose to monitor the Yankee cylinder surface.